1. Field of the Invention
This invention is in the field of internal combustion engines and particularly the field of internal combustion engines capable of running efficiently on char fuels or on high viscosity residual liquid fuels alone or in combination.
2. Description of the Prior Art
Many of the appropriate features of the Prior Art are described in the "Description of the Prior Art" portions of the cross referenced related applications and this material is incorporated herein by reference thereto.
The term engine cylinder is used herein and in the claims to include also the cylinder head if used. The term piston crown is used herein and in the claims to mean that piston surface facing the combustion chamber space. The term combustion chamber space is used herein and in the claims to mean that space fully enclosed by the engine cylinder and the piston crown when said space is of minimum volume during the compression process, which is commonly at the piston top dead center position of compression.
When steam is admitted along with the air during the intake process of an internal combustion engine less air enters the engine per cycle due to displacement by the steam. This reduction of engine air volumetric efficiency reduces engine torque capability.
As discussed in the paper, "Studies Of The Effects Of Water On Gasoline Engine Wear At Low Temperature," Wear, Vol. 10, 1967, pgs 33-48, increasing the steam content of the expansion gases of an internal combustion engine can increase engine corrosive wear or depletion of basic lubricating oil additives.
Excess unreacted steam also acts to reduce engine efficiency by increasing the exhaust gas enthalpy losses.
Hence where steam is desired to be used in an internal combustion engine we prefer to use the least possible amount of steam for reasons of engine efficiency and engine wear, and we also prefer not to admit such steam during the engine intake process.